Does an adjustment have to make a noise to be effective?

No, it is a common misconception that your joints must make a noise to be properly adjusted. However, more often than not when your vertebrae are adjusted, the smooth articular (joint) surfaces become separated, creating and then releasing a small vacuum, making a noise. This is the sound made when you crack your knuckles. Your chiropractor is concerned with the position of your vertebrae, not with the noise that may occur.